The present invention relates to an apparatus for processing image data to produce an image for display on a display screen and, more particularly, to produce a high quality image for display on a relatively large display screen.
Moving pictures, such as those produced for display on “the big screen” at cinemas are usually provided by way of 35 mm film that is projected onto a relatively large screen. The use of conventional graphics processors (employing computers, microprocessors, etc.) to produce moving pictures is becoming more popular inasmuch as state of the art graphics processors are becoming more sophisticated and capable of producing quality images. As a practical matter, however, conventional graphics processors are designed to produce moving pictures on a computer display screen (such as a 17-inch monitor), a conventional television screen, etc., and not on relatively large screens, such as those found in cinemas. Indeed, conventional graphics processors are not capable of processing image data at a sufficient speed to produce moving pictures of sufficient quality, particularly when the moving pictures are to be displayed on a relatively large display screen.
The processing limitations of conventional graphics processors affects image quality in two basic ways, namely, the resolution (e.g., the total number of pixels available for each frame of image data) is insufficient for relatively large display screens, and the frame rate (e.g., the number of frames of image data produced each second) is insufficient to meet or exceed the frame rate for the 35 mm film cinematography protocol.
With reference to FIG. 1, a conventional graphics processor 10 may include three basic components, namely, a processing unit or software processor 12, a rendering unit 14, and a frame buffer 16. At its core, the conventional graphics processor 10 receives image data, including data concerning primitives (e.g., polygons used to model one or more objects of the image to be displayed) and produces a series of frames of image data (or pixel data), where each frame of image data contains the information necessary to display one frame of the image on the display screen. When these frames of image data are displayed at a sufficient frame rate, the appearance of movement is achieved.
The software processor 12 manipulates the image data to obtain a sequence of instructions (such as polygon instructions) for input to the rendering unit 14. The rendering unit 14 receives the sequence of instructions and produces pixel data, e.g., pixel position, color, intensity, etc. The pixel data is stored in the frame buffer 16 and an entire frame of the pixel data is referred to herein as frame image data. The frame buffer 16 is usually sized to correspond with the resolution of the display screen such that enough pixel data to cover an entire frame of the display screen may be stored. When a full frame of image data are stored in the frame buffer 16, the frame image data are released from the frame buffer 16 to be displayed on the display screen.
Among the processing bottlenecks caused by the conventional graphics processor 10 of FIG. 1 that affect processing speed is the rate at which the software processor 12 and rendering unit 14 can produce the frame image data. In order to ameliorate this bottleneck, it has been proposed to provide a graphics processor 20 having parallel software processing/rendering units 18 as illustrated in FIG. 2. The output from these parallel processing units 18 are input to a single frame buffer 16 from which the frame image data are released for display on the display screen. Although the graphics processor 20 of FIG. 2 ameliorates one of the processing bottlenecks by increasing the rate at which the image data are processed and rendered, just like peeling back the layers of an onion, an additional processing bottleneck emerges. Indeed, the rate at which the frame image data can be stored into the frame buffer 16 and released therefrom is insufficient to adequately meet the data throughput requirements for producing a high quality moving picture on a relatively large display screen.
Accordingly, there is a need in the art for a new apparatus and/or method for providing graphics processing that significantly increases processing speed such that high resolution moving pictures may be produced for display on a large display screen.